Drag a RadDatePicker from the toolbox onto the Template Design Surface and set its Skin property to "Inox":

Choose End Template Editing from the RadToolBar Smart Tag:

Run the application. Click on the first three buttons on the toolbar ("A", "B", and "C") and note how they function as a radio group. Click on the "Details" button to expand its drop-down list. Note the separator you added, and the date picker, which you can click to select a date:

Click the "Add Item" button, and note that its appearance changes to respond to the click, but the drop-down does not appear unless you click the drop-down arrow: